A combine harvester of this type is described in detail in the European patent applications no. EP 1 529 434 and EP 2 000 018 which are incorporated herein by reference in their entirety. In these patent applications, crop residue directed along the first path is deposited in a swath on the ground for subsequent baling, that directed along the second path being comminuted by a chopper before being spread onto the ground and that directed along the third path being evenly spread over the ground by a spreader. Crop residue is directed to flow along the first path when both doors are in their first positions, along the second path when the first door is in its first position and the second door in its second position, and along the third path when both doors are in their second positions.
FIGS. 1A, 1B and 1C of the accompanying drawings represent schematically the positions of the doors of the guide mechanism as shown in FIGS. 4, 12 and 7 respectively of EP 1 529 434 and FIGS. 1A, 1B and 1C respectively of EP 2 000 018.
In FIG. 1A, the two deflection doors 96 and 94 are shown in their first positions corresponding to the first flow path, which is represented by the arrow F. In this position, the combine harvester is operating in its first processing or swathing mode. In this figure, the crop residue transported by the conveyer 78 passes over the second door 94 and is discharged as a narrow swath from the rear of the combine harvester.
In FIG. 1B, corresponding to the second flow path, the first door 96 is still in its first position but the second door 94 is moved to its second position to uncover the chopper 88. In this position, the combine harvester operates in its second processing or chopper mode. All the crop residue from the conveyer 78 is now funnelled into the chopper 88 in which it is comminuted before it is discharged onto the ground.
In FIG. 1C, corresponding to the third flow path, the two deflection doors 96 and 94 are in their second positions. In this configuration, the combine harvester operates in its third processing or spreader/corn mode. The raised second door 94 (also called the chop or swath door) prevents the crop residue from being discharged from the rear of the combine harvester, while the pivoting of the first door 96 (also called the deflector or kickback door) towards its second position prevents the crop from entering into the chopper 88. As a result, the crop residue follows a path that leads to a chaff spreader (not shown in the drawings) which distributes it evenly over the ground.
The focus of the present invention is the mechanism employed to move the two deflection doors and to hold them in position while the harvester is operating in any one of the three possible processing modes of the harvesting machine for processing the crop residue.
EP 1 529 434 teaches connecting each of the doors to a handle to enable the doors to be moved manually and it also proposes automatic positions of the doors, be it electronically, hydraulically or mechanically. Manual positioning of the doors is clearly the simplest and least expensive solution but some form of latching or locking mechanism is required to hold each of the two doors firmly in their end positions. Repositioning of manually operated doors in EP 1 529 434 therefore requires each of the handles to be separately unlatched before the doors are repositioned and latched after the doors have been moved to the desired position. In order to simplify the latching of manually operated doors in a combine harvester of the type described above so that, without intervention from the operator, each of the doors is held firmly against movement and vibration in each of its two end positions, in EP 2 000 018, a combine harvester is disclosed having a threshing mechanism for separating harvested crop into grain and crop residue, and a guide mechanism for directing the flow of crop residue from the threshing mechanism along one of three paths, the guide mechanism comprising two deflection doors that can each be moved between two end positions, wherein each of the doors of the guide mechanism is supported on a pivot shaft fitted with a crank arm and a resilient element connecting the two crank arms to one another in such a manner that each door, independently of the position of the other door, is urged by the resilient element to remain in one of two stable end positions and passing through an unstable over-centre position when moved from one stable end position to the other.
The problem of the combine harvesters as disclosed in EP 1 529 434 as well as in EP 2 000 018 is that the handles 94a and 96a still have to be turned manually by the operator to set the two doors 96 and 94 in the desired processing mode of the crop residue. Therefore, with this current design, the operator needs to leave the cab to switch from the different processing modes of the crop residue.
Therefore, there exists a need to be able to switch automatically and remotely between the different processing modes of a harvesting machine.